This invention relates to a spray nozzle capable of preventing sludge intrusion therein even in a case where the spray nozzle is placed within a sludge substance. This invention also relates to an apparatus in which spray nozzles of this kind are utilized.
Heretofore, spray nozzles have been widely used for spraying a liquid substance over an article for cleaning or cooling the article or for depositing and drying the substance on the surface of the article. However, since most of the conventional spray nozzles have no reverse-flow preventing mechanism, when the nozzle 1 is placed in a sludge 3 contained in a vessel 2 as shown in FIG. 1 of the accompanying drawings, some part of the sludge inevitably intrudes inside of the spray nozzle, thus causing deposition of the sludge and clogging of the liquid passage in the spray nozzle.
A specific type of conventional spray nozzles includes a reverse flow preventing mechanism as shown in FIG. 2, the nozzle comprising a stem part 5 having a liquid passage 6 therein, a nozzle cap member 13 having an injecting hole, 4, the stem part 5 and the nozzle cap member 13 defining a chamber 7 having a larger diameter than that of the fluid passage 6, and a spherical valve member 9 encased in the chamber 7 so as to be urged by a spring 8 toward the passage 6 opening in the chamber 7.
It is apparent, however, that the conventional spray nozzle of the above described construction cannot prevent the sludge from intruding into the chamber 7 through the injecting hole 4 when the spray nozzle is placed in the sludge. A part of the sludge intruded in the chamber 7 tends to be solidified and compacted by the reciprocating movement of the spherical valve member 9, so that the interior of the chamber 7 and injecting hole 4 are clogged by the compacted sludge.